MultiRoombaRover/mediamtx_server_integration.md

mediaMTX Integration

Each rover runs mediaMTX locally to capture the Pi camera, and the control server hosts a central mediaMTX instance that fans video out to drivers and spectators. When a rover connects, the Node server asks the central mediaMTX to pull the rover’s local WHEP stream and expose it under the rover’s name.

Pi (publisher)

• mediaMTX samples the Pi camera (paths.rovercam.source: rpiCamera) and exposes the HTTP API on http://127.0.0.1:9997.
• roverd automatically detects the Pi’s own WHEP endpoint (e.g. http://roomba-alpha.local:8889/whep/rovercam) and reports a bridgeWhepUrl (converted to whep://.../whep) to the server. No manual per-rover video URL configuration is required.
• The media.manage flag keeps the local service alive via systemctl and hits the API for health checks (media.healthUrl, defaults to http://127.0.0.1:9997/v3/paths/list).

Control server (viewer)

• The central mediaMTX instance serves WHEP playback at /whep/<roverId> and exposes its control API on http://127.0.0.1:9997.
• When a rover connects, the Node server calls POST /v3/config/paths/replace/<roverId> and sets source: whep://<pi-ip>:8889/rovercam/whep. When the rover disconnects, the path is removed.
• Viewers still use video:request to obtain a session token. They POST their SDP offer to /whep/<roverId> with Authorization: Basic base64(token:token). mediaMTX forwards the token to /mediamtx/auth (in the user field) before allowing the stream to start, and the Node server enforces lockdown/role rules there.

Driver / spectator UIs

• When a user requests video the browser asks the Node server for a session token, and if the current mode/role allows it, the server returns the WHEP URL plus the session id.
• Spectator mode and lockdown are enforced purely on the Node server: no direct Pi URLs are ever exposed, and once a user has a session it remains valid until they disconnect or lockdown revokes it.